OK, here's the fix for my High CO and Poor hot starting which actually manifested into a mis-fire on 1 or 2 cylinders - FUEL INJECTORS!!
I bought a set of Delphi (Rochester) injectors off ebay:http://www.ebay.co.uk/itm/Set-of-4-BRAN ... SwxCxT9R52
I'd completed several diagnostics before buying the injectors with the help of Pete, another LEC member is Essex. We confirmed the ignition system was ok and also the ECU. Pete brought his Elan around and we swapped ECU's. My ECU in his car was fine so we knew it wasn't my ECU drivers. So we checked resistance across injectors and two were showing low resistance so noW I was almost certain, fuel injectors were the root cause of my problem!
I followed the WikiLEC process for Fuel Injector removal and re-fit. There are 3 small errors on the WikiLEC page: First error, no mention of relieving the fuel pressure before starting. On RHD Elans, the fuel cut off is under the hood stowage, close to the battery. Simply push the fuel cut off switch down and pull back up when you want to re-start. Following the WikiLEC instructions 2. The bolts holding the plastic wire cover are 10mm not 12mm and 6. The 14mm fuel rail bolts are 12mm. I'd already removed the injector harness wire clips (which are a sod of a job), with a metal tooth pick you can buy from a dentist. The next most difficult item is 5. Removing and catching the T26 Torx screw securing the fuel pressure regulator. On re-fit, do be careful not to slice any fuel injector O rings, the clips that hold the injectors in place on the rail are close and I managed to cut one of mine. Annoyingly, I didn't discover this until I'd completed the work and I had a floor of fuel on key on. Also dont remove the injector to rail clips as they are difficult to secure back on the rail. I suspect these clips aren't actually required as the injectors are captive between the cylinder head and fuel rail that are bolted together. I suspect the clips were merely an assembly aid to keep the injector and rail together when assembling in the engine plant. Be careful not to lose the T26 Torx screw on re-assembly of the fuel pressure regulator. Press a bit of blutak into the Torx drive to secure the screw to the socket and carefully start the screw into the thread. I've purchased a extendable magnetic stick which is really useful for catching or finding screws as they fall!
So, a couple of hours later, second start after fixing the fuel leak and everything fired up. Fantastic! No mis-fire at all. I then checked my CO level with a Gunson CO meter. It was running very rich ~8% before, now its <1%. Make sure any CO check is done when the engine is Hot, after the cooling fans have cycled. I then switched off and did a hot start. She started immediately, so the hot start issue is also fixed. I'm feeling rather chuffed now!!!